Vitamin D and critical illness: what endocrinology can learn from intensive care and vice versa

The prevalence of vitamin D deficiency in intensive care units ranges typically between 40 and 70%. There are many reasons for being or becoming deficient in the ICU. Hepatic, parathyroid and renal dysfunction additionally increases the risk for developing vitamin D deficiency. Moreover, therapeutic interventions like fluid resuscitation, dialysis, surgery, extracorporeal membrane oxygenation, cardiopulmonary bypass and plasma exchange may significantly reduce vitamin D levels. Many observational studies have consistently shown an association between low vitamin D levels and poor clinical outcomes in critically ill adults and children, including excess mortality and morbidity such as acute kidney injury, acute respiratory failure, duration of mechanical ventilation and sepsis. It is biologically plausible that vitamin D deficiency is an important and modifiable contributor to poor prognosis during and after critical illness. Although vitamin D supplementation is inexpensive, simple and has an excellent safety profile, testing for and treating vitamin D deficiency is currently not routinely performed. Overall, less than 800 patients have been included in RCTs worldwide, but the available data suggest that high-dose vitamin D supplementation could be beneficial. Two large RCTs in Europe and the United States, together aiming to recruit >5000 patients, have started in 2017, and will greatly improve our knowledge in this field. This review aims to summarize current knowledge in this interdisciplinary topic and give an outlook on its highly dynamic future.

Management of pinna haematoma study (MaPHaeS): A multicentre retrospective observational study

OBJECTIVES

To assess current variation in the management of pinna haematoma (PH) and its effect on outcomes.

DESIGN

Multicentre retrospective observational record-based study.

SETTING

Eleven hospitals around the UK.

PARTICIPANTS

Eighty-three patients above the age of 16 with PH.

OUTCOME MEASURES

The primary outcome measure was recurrence rate of PH over a 6-month period post-treatment, assessed by treatment type (scalpel incision vs needle aspiration). Secondary outcome measures assessed the impact of other factors on recurrence, infection and cosmetic complications of PH over a period of 6 months.

RESULTS

After adjusting for confounding factors, involvement of the whole ear, and management within an operating theatre were associated with a lower rate of recurrence of pinna haematoma. The drainage technique, suspected aetiology, choice of post-drainage management, grade and specialty of practitioner performing drainage, the use of antibiotic cover and hospital admission did not affect the rate of haematoma recurrence, infection or cosmetic complications.

CONCLUSIONS

Where possible PH should be drained in an operating theatre. Multicentre randomized controlled trials are required to further investigate the impact of drainage technique and post-drainage management on outcome.

Self-Reported Use of Complementary and Alternative Medicine among the Health Care Consumers at a Tertiary Care Center in Ajman, United Arab Emirates

Background:

Complementary and alternative medicine (CAM) covers a wide range of approaches, including herbal medicine, manual healing techniques, traditional therapies and mind-body interventions. CAM is widely used throughout the world to treat a variety of illnesses and to maintain health.

Aim:

Complementary and alternative medicine (CAM) is popular across the world, and is widely practiced. Utilization pattern and reasons for use and non-use among patients attending a tertiary care center are assessed in this study.

Subjects and Methods:

One hundred and thirty-five patients of different nationalities, above the age of 18 years, Gulf Medical College Hospital and Research Centre, Ajman, UAE, were interviewed using an open-ended structured questionnaire. In addition to socio-demographic characteristics, the acceptability, utilization pattern and reasons for use and non-use were elicited from the participants after obtaining consent from them. PASW 18 version was used to perform Chi-square test and descriptive statistics.

Results:

Among the 135 participants were 20-81 years old, those from the Far East used most 85.7% (6/7), then Pakistan 38.5% (15/39) and India 23% (16/70). The most common system used was homeopathy. Physicians advised 28.2% (11/39) of users, whereas others used non-medical information. Around 71.8% (28/39) reported good outcome for themselves and family; however, only 10% (4/39) recommended it to others. Most of the users, 75% (101/135), were not sure whether CAM was based on scientific evidence, while 18% (24/135) felt it was. Good previous experience and less treatment complications were the most common reasons for using CAM and non-use due to lack of knowledge or need.

Conclusion:

About one-third of the seekers of modern medicine care also use CAM, and mostly without physician advice; hence, the importance of discussing the same while taking the clinical history. In view of the belief that CAM has fewer side-effects, there is even more need for physician-initiated discussion.

Use of Social Networking Sites among University Students in Ajman, United Arab Emirates

Note: a new paragraph 'What this study adds:' was added to page 250 on 27 March 2014.Background    Social networking sites are web-based services through which individuals can create a public or semi-public profile within a bounded system, connect with a list of other linked users, and view and interact with a list of their connections and with those made by others within the system. To estimate the proportion of university students using social networking sites (SNS) and to determine the association between SNS use and age, gender, nationality, course and year of study, living context, family size, number of close friends, close relationships, stress related to studies and interpersonal relationships. Materials and Methods A cross sectional study was carried out among 300 students from two universities in Ajman, UAE. A self-administered, content-validated and pilot-tested questionnaire was used. The participants answered questions related to their use of social networking sites and details of socio-demographic variables. The data collected were entered into Microsoft Excel and transferred to PASW 18.0 version. Data were analyzed as frequencies, percentages, means and SDs, and Chi-square test used for associations. The odd ratio was calculated for the significant variables to find the degree of association. The SNS usage was categorized as average, moderate or high based on mean and SD on the SNS test score.  Results The study population was comprised of 41.6% males and 58.3% females. 89% used social networking sites (SNS) and 11% were non-users. Of the 267 users of SNS, 58.8% were average users, 37.8% moderate users and 3.4% high users. Students in the first and second years of study, small family size, age below 20 years, male gender, being in a non-medical study program, friends in close relationship were found to be associated with higher SNS use. Conclusion Social networking sites were found to be popular among a large number of university students in the UAE, this being more so among males and non-medical students of first two years of study. DOI: http://doi.dx.org/10.3126/nje.v3i2.8512

Congenital Anomalies at Birth: A Hospital Based Study in UAE

Introduction: It is widely acknowledged that congenital anomalies heavily contribute to infant morbidity and mortality worldwide, with an estimated 9 million infants (7% of all births) born annually having a serious congenital anomaly that result in death or lifelong disability. The objective of our study was to estimate the frequency of congenital anomalies at the Gulf Medical College Hospital and Research Center, Ajman and to estimate the proportion of births with congenital anomalies per 1,000 live births. Materials and Methods: It was a Hospital-Record based descriptive study of the 1,222 consecutive live births from December 2007 to June 2008. Results: There were 84 cases of congenital anomalies among the 1,222 live births; the rate of anomalous births was 68.7 per 1,000 live births or 6.9%. Anomalies of the genitourinary system (40.5%) were the most common, followed by musculoskeletal (28.6%) and cardiovascular (10.7%). Gastrointestinal, chromosomal and multiple system anomalies accounted for 3.6% each and miscellaneous anomalies were seen in 7.1%. Central Nervous system (2.4%) anomalies were the least. Congenital hydrocele (19.0%) was seen to have the highest frequency amongst all recorded anomalies, followed by Talipes or Clubfoot (14.3%). 9.3% of the male and 4.3% of the female population of live births had a congenital anomaly. Birth Weight (p=0.005) and Gender (p=0.001) were found to have significant association with the frequency of birth defects. Maternal Age, gravidity, parity, previous abortions, VDRL and Hepatitis B status, Gestational Diabetes, Pregnancy Induced Hypertension, gestational age, maternal and infant blood group, nationality and consanguinity showed no statistically significant association with congenital anomalies. Conclusion: The proportion of congenital anomalies found in our study is alarmingly high and emphasizes the need for more accessible nationwide screening, counseling and surveillance systems. J. Nepal Paediatr. Soc. 32(2) 2012 105-112 doi: http://dx.doi.org/10.3126/jnps.v32i2.5995

Pattern of Blood Pressure Distribution among University Students in Ajman, United Arab Emirates

Background Elevated blood pressure has been identified as a silent killer contributing to mortality and morbidity worldwide, hence it is essential to identify the high risk individuals at an early age to prevent the progress of the disease and its co-morbid conditions. Objective The objective of the present cross-sectional study was to assess the pattern of blood pressure distribution among students of medical and allied health professions at Gulf Medical University (GMU) Ajman, United Arab Emirates (UAE). Methods The study was conducted from November 2009 to February 2010. GMU has academic programmes such as Bachelor of Medicine, Physical therapy, Pharm D and Dental Medicine with a multiethnic student population. A pretested structured instrument used for data collection and blood pressure was measured using mercury sphygmomanometer. Descriptive statistics such as means and standard deviation were used to summarize the quantitative variables. The association of age, gender and nationality with systolic and diastolic blood pressure was determined by Pearson's correlation coefficient and a p-value ≤ 0.05 was considered statistically significant. Results The systolic and diastolic blood pressures were evenly distributed across all students irrespective of their age. A significantly higher systolic blood pressure in males was observed when compared to females, but the difference was not significant in diastolic blood pressure. In the present study among medical and allied health science students, the distribution of blood pressure was not associated with age. The mean systolic blood pressure and diastolic blood pressure were seen to be higher among Arabs when compared to Non-Arabs though not statistically significant. Family history of metabolic diseases did not show any association with the mean blood pressure. Conclusion There was a strong association for developing hypertension among male when compared to female gender. Key Words: University students; Age; Gender; Nationality; Systolic blood pressure; Diastolic blood pressureDOI: http://dx.doi.org/10.3126/nje.v1i3.5572 Nepal Journal of Epidemiology 2011;1(3) 86-89

The Use of Obesity Indicators for the Prediction of Hypertension Risk among Youth in the United Arab Emirates

BACKGROUND

Obesity is a significant risk factor for metabolic disorders including increase in blood pressure. Body mass index (BMI), waist circumference (WC) and Waist/Hip ratio (WHR) are simple and effective indicators of obesity. The objectives of this study were to examine the relationships between obesity anthropometric indicators and hypertension and to identify the best anthropometric indicator/s that can predict hypertension risk among youth in the UAE.

METHODS

A 110 first year students in a Medical University in Ajman, UAE, during the year 2009-2010 were included in a cross-sectional study. The height, weight, WC, hip circumference and blood pressure were measured and the BMI and WHR were calculated for each student and used in the analyses.

RESULTS

The mean values for BMI, WC, hip circumference and WHR, were significantly higher in the Pre/Hypertensive group compared to normal blood pressure group. The risk of Pre/ hypertension was significantly increased by 4.3 times for participants who had general obesity (BMI≥ 30) or abdominal obesity (identified from high WC). Highly significant correlations were noticed between systolic and diastolic blood pressure and all anthropometric indicators except that for Hip circumference and systolic blood pressure. Step-wise linear regression model showed that when all obesity indicators were studied together, the waist circumference was the only indicator which showed significant relationship with both systolic and diastolic blood pressure.

CONCLUSION

Waist circumference is the best anthropometric indicator that can predict hypertension risk among youth in the UAE.

Introducing geriatric health in medical training in Ajman, United Arab Emirates: A co-curricular approach

BACKGROUND

Medical students' knowledge and understanding of the elderly will affect the quality of care to the rising population of older adults which points to a need to identify geriatric health training methods appropriate for the region and curriculum. Therefore the study assessed the effect of a co- curricular introductory workshop on knowledge regarding geriatric health and attitude towards the elderly among fourth year medical students in a medical university

METHOD

A quasi-experimental before-after study, with control was conducted at Gulf Medical College among 60 medical students from discipline-based curriculum in year IV during May-June 2010 of whom 16 had opted (attendees) to undergo the introductory course, a five day workshop of 10 hours duration. Pre- and post-testing used self-administered questionnaires for demographic variables: age, gender, nationality, close contact with older people; a quiz on old people's health, and Kogan's Old People Scale (KOPS) for attitude. The difference in scores on quiz and KOPS were compared for the attendees and 26 non-attendees who participated in both pre and post testing.

RESULTS

The attendees group had 38% male and 62% female participants and the non-attendees group had 21% and 79% respectively. The groups were not significantly different in age, sex, nationality and close contact with the elderly. The scores on the quiz and KOPS showed no statistically significant difference between the two groups before or after the workshop. Almost all the participants evaluated the workshop very positively especially the interaction with healthy elderly and inmates of old people's home.

CONCLUSION

A 10-hour introductory co-curricular workshop made no significant change in the knowledge on geriatric health or attitude of fourth year medical students though they reported it as a very enriching experience. A reflective report may have been a better assessment tool and the impact on their clinical practice cannot be predicted.

Effect of alpha-interferon and alpha-tocopherol in reversing hepatic cirrhosis in rats

The aim of this study was to assess the effects of alpha-interferon and alpha-tocopherol (vitamin E), or a combination of both, in reversing hepatic fibrosis following the induction of cirrhosis using thioacetamide by histological and biochemical analysis. Fifty male Wistar rats were used in this study. The animals were divided equally into five groups. Animals in group I were used as controls. The remaining animals (groups II-V) were provided with 0.5 g/L of thioacetamide in order to induce liver cirrhosis. Group II animals were used as the cirrhotic control. Animals of groups III, IV and V were given alpha-interferon, alpha-tocopherol and interferon together with alpha-tocopherol, respectively, for 30 days. After 30 days the animals were killed and following gross morphological examination of the liver, the hepatic tissues were processed for histological analysis and the serum was used for liver function tests. Morphological analysis showed a decrease in the number of nodules on the surface of the liver in both interferon- as well as vitamin E-treated cirrhotic rats. Histopathological analysis showed that the abnormalities of the cirrhotic liver were partially reversed and liver function tests showed an overall improvement following treatment of animals of groups III, IV and V. Combination therapy using both interferon and alpha-tocopherol did not have any substantial effect on the rats compared with that when they were given separately. These findings suggest that alpha-interferon and alpha-tocopherol may have therapeutic value in reversing liver cirrhosis.

Cytosolic delivery of antisense oligonucleotides by listeriolysin O-containing liposomes

Antisense oligodeoxynucleotides (ODNs) possess great potential as sequence-specific therapeutic agents. Sufficient concentrations of intact ODN must bypass membrane barriers and access the cytosol and nucleus, for ODNs to be therapeutically effective. A cytosolic delivery strategy was designed to improve the efficiency of ODN delivery in bone-marrow-derived macrophages. This liposome-based formulation utilizes listeriolysin O (LLO), the endosomolytic hemolysin from Listeria monocytogenes, to mediate the escape of ODN from endocytic compartments into the cytosol. To monitor the cytosolic delivery of ODN, subcellular trafficking of fluorescently labeled ODNs was visualized using epifluorescence microscopy. The expression of target protein and mRNA after delivery was measured using flow cytometry and Northern blot analysis, respectively. ODN specific for murine intercellular adhesion molecule-1 (ICAM-1) encapsulated in LLO-liposomes was released to the cytosol and trafficked to the nucleus, efficiently and specifically suppressing activation-induced expression of ICAM-1 at both protein and mRNA levels. Delivery without LLO resulted in sequestration of ODN in vesicular compartments leading to little inhibition of ICAM-1 expression, which supports the requirement of LLO for efficient cytosolic delivery using this system. The data clearly demonstrate that LLO-mediated escape of ODN from intracellular vesicles is an effective approach to achieve full therapeutic antisense activity in cultured macrophages.

Lrp binds to two regions in the dadAX promoter region of Escherichia coli to repress and activate transcription directly

The dadAX operon is expressed by multiple promoters that are repressed by leucine-responsive regulatory protein (Lrp) and activated by cyclic AMP-CRP. In previous work, we found that alanine or leucine acted as inducers to antagonize Lrp repression of the three major promoters directly. Here, we identify 11 Lrp binding sites located within 350 bp of dad DNA. A mutational analysis, coupled with in vivo and in vitro transcription experiments, indicated that Lrp sites that overlap the dad promoters were involved in repression. In contrast, sites upstream of the promoters did not appear to be necessary for repression, but were required for activation by Lrp plus alanine or leucine of one of the major dad promoters, P2. This activation by alanine or leucine was not simply relief of repression, as P2 transcription from a constitutive template was increased fivefold compared with the basal level of transcription found in the absence of Lrp and the co-activator cyclic AMP-CRP. Alanine or leucine decreased the affinity of Lrp to repressor sites, while having little or no effect on the binding of Lrp to activator sites. This differential effect of alanine and leucine on Lrp binding helps to explain how these modifiers influence both repression and activation of the dad operon.

Influence of dextran molecular weight on capture in and release from decylamine carboxymethylcellulose capsules

A series of dextran molecular weight markers were encapsulated in decylamine carboxymethylcellulose microcapsules to serve as probes of capsule retentivity. The capsules were prepared by allowing microdrops of aqueous sodium carboxymethylcellulose to fall into aqueous decylamine acetate solution. Salt exchange reaction at the droplet pseudointerface resulted in self-assembling films which essentially instantaneously enclosed the droplets. Concentrations of anionic polymer were varied in the range from 1-3%. Chromophore-bearing dextrans were incorporated into these capsules by blending the dextrans with the carboxymethylcellulose prior to the encapsulation step. Four dextrans of differing (light scattering) molecular weights were used: 2 x 10(6), 6 x 10(5), 7 x 10(4), and 1.9 x 10(4) amu. The mass balance of dextran retained in the capsules, released on washing the capsules or which escaped encapsulation was determined spectrophotometrically. To measure total dextran in a population of washed capsules, the capsules were lysed in a 0.3 M solution of sodium chloride. To monitor dextran release, washed capsules were suspended in water and dextran concentration in the supernatant was measured. Encapsulation efficiency exceeded 80% for high molecular weight dextran but was lower with the smaller dextrans.

Extracellular enveloped vaccinia virus is resistant to complement because of incorporation of host complement control proteins into its envelope

Vaccinia virus (VV) produces two antigenically and structurally distinct infectious virions, intracellular mature virus (IMV) and extracellular enveloped virus (EEV). Here we have investigated the resistance of EEV and IMV to neutralization by complement in the absence of immune antibodies. When EEV is challenged with complement from the same species as the cells used to grow the virus, EEV is resistant to neutralization by complement, whereas IMV is not. EEV resistance was not a result of EEV protein B5R, despite its similarity to proteins of the regulators of complement activation (RCA) family, or to any of the other EEV proteins tested (A34R, A36R, and A56R gene products). EEV was sensitive to complement when the virus was grown in one species and challenged with complement from a different species, suggesting that complement resistance might be mediated by host RCA incorporated into the EEV outer envelope. This hypothesis was confirmed by several observations: (i) immunoblot analysis revealed that cellular membrane proteins CD46, CD55, CD59, CD71, CD81, and major histocompatibility complex class I antigen were detected in purified EEV but not IMV; (ii) immunoelectron microscopy revealed cellular RCA on the surface of EEV retained on the cell surface; and (iii) EEV derived from rat cells expressing the human RCA CD55 or CD55 and CD59 were more resistant to human complement than EEV derived from control rat cells that expressed neither CD55 nor CD59. These data justify further analysis of the roles of these (and possible other) cellular proteins in EEV biology.

Pharmacologic management of depression in the elderly

Depression, the most common geriatric psychiatric disorder, is a disabling mood disorder that impairs one's well-being and may even threaten a sufferer's life. Severely depressed elderly persons are more likely to kill themselves than individuals in any other age group. However, geriatric depression is, for the most part, a treatable and manageable illness. Antidepressant medication can be very effective in treating major depressive disorder (MDD). Because age-related physical changes in the elderly produce pharmacokinetics that are often different than that experienced by younger adults, different doses are often necessary. This article summarizes recommendations for selecting and initiating appropriate antidepressant therapy in elderly persons suffering from MDD. The benefits and drawbacks of tricyclic antidepressant agents, and other atypical antidepressant agents are discussed. Phases of treatment, drug selection, dosing, and educational tips for pharmacotherapy are presented.

In vitro and in vivo characterization of three major dadAX promoters in Escherichia coli that are regulated by cyclic AMP-CRP and Lrp

We have shown previously that the dadAX operon of Escherichia coli expresses multiple transcripts, which are repressed by leucine-responsive regulatory protein (Lrp). Here we used site-directed mutagenesis and in vitro and in vivo transcription assays to show that each of the three major dad transcripts requires a specific promoter. These promoters, P1-P3, overlap and are positively regulated in vivo by cyclic AMP-CRP. DNase I footprinting experiments localized two CRP binding sites in this region: CRP1, which is positioned upstream of P1-P3, and CRP2, which is located within the promoters. Site-directed mutagenesis of each site provided evidence that CRP1 is necessary for the effects of cyclic AMP-CRP on dad expression in vivo and in vitro, and that CRP2 probably plays little or no role in this process.

The extracellular domain of vaccinia virus protein B5R affects plaque phenotype, extracellular enveloped virus release, and intracellular actin tail formation

Vaccinia virus produces two morphologically distinct forms of infectious virus, termed intracellular mature virus (IMV) and extracellular enveloped virus (EEV). EEV is important for virus dissemination within a host and has different surface proteins which bind to cell receptors different from those used by IMV. Six genes are known to encode EEV-specific proteins. One of these, B5R, encodes a 42-kDa glycoprotein with amino acid similarity to members of the complement control protein superfamily and contains four copies of a 50- to 70-amino-acid repeat called the short consensus repeat (SCR). Deletion of B5R causes a small-plaque phenotype, a 10-fold reduction in EEV formation, and virus attenuation in vivo. In this study, we inserted mutated versions of the B5R gene lacking different combinations of the SCRs into a virus deletion mutant lacking the B5R gene. The resultant viruses each formed small plaques only slightly larger than those of the deletion mutant; however, the virus containing only SCR 1 formed plaques slightly larger than those of viruses with SCRs 1 and 2 or SCRs 1, 2, and 3. All of these viruses produced approximately 50-fold more infectious EEV than wild-type virus and formed comet-shaped plaques under liquid overlay. Despite producing more EEV, the mutant viruses were unable to induce the polymerization of actin on intracellular virus particles. The implications of these results for our understanding of EEV formation, release, and infectivity are discussed.

Lrp is a direct repressor of the dad operon in Escherichia coli

Expression of the degradative D-amino acid dehydrogenase (dad) operon is known to be increased when Escherichia coli is grown in the presence of D- or L-alanine. Alanine is thought to act as an inducer to block the action of a postulated repressor. This operon is also believed to be regulated by catabolite repression. We have used in vivo and in vitro experiments that show that the dad repressor is the leucine-responsive regulatory protein (Lrp). dad expression in a dad-lacZ operon fusion strain was increased four- to sevenfold when cells were grown in minimal medium containing alanine or leucine. A strain lacking Lrp had high-level constitutive dad expression. Gel retardation and footprinting studies revealed that Lrp binds in vitro to multiple sites over a large area in the dad promoter region. This binding was reduced by alanine or leucine. In vitro transcription assays, using a plasmid template and primer extension analysis, identified three major dad transcripts (Tr1, Tr2, and Tr3). The formation of these transcripts was differentially regulated by cyclic AMP-cyclic AMP receptor protein complex, and each was strongly repressed by Lrp. Alanine or leucine completely (for Tr1 and Tr2) or partially (for Tr3) reversed Lrp inhibition. Site-directed mutagenesis of an Lrp binding site strongly reduced Lrp binding and prevented Lrp repression of dad transcription in vivo and in vitro. Taken together, these results strongly suggest that Lrp and alanine or leucine act directly to repress and induce, respectively, transcription of the dad operon.

Safe motherhood: when to begin

Two thousand five hundred college girls were assessed for their knowledge and attitudes regarding sex, pregnancy and child rearing with the help of a pretested questionnaire. The site of menstruation was known to only 35.3% of the girls. The knowledge about the time and site of conception was 25.3% and 58.2%, respectively. Only 16.3% of the respondents knew the normal route of delivery although the duration of normal pregnancy was known to majority (87.7%). The girls were aware of the ideal timing of abortion (67.5%) but the safe method and legality were poorly known facts. Only 5% of the girls believed in pre-marital sex. More than half (54.9%) of the girls knew about some form of contraceptive, Copper-T being the best known. Nearly one fifth of the girls were either undecided or wished family members to decide about antenatal check-ups. The need for better diet and injections during pregnancy was well known although few (15.2%) were aware of the injections being tetanus toxoid. Only about 10% wanted a home delivery but one fourth felt that a Dai or a relative was suitable for conducting the delivery. An overwhelming majority of the students stated that knowledge about above facts was important and they would like to learn about them preferably during college education. It is recommended that 'Family life education' be provided during pre-adolescent and adolescent years to ensure a safe motherhood and a healthy child.

The role of integration host factor in gene expression in Escherichia coli

Integration host factor is a sequence-specific, histone-like, multifunctional DNA-binding and -bending protein of Escherichia coli. The characterization and functional analysis of this protein has been done mainly in bacteriophage lambda and other mobile genetic elements. Less is known concerning the role of integration host factor (IHF) in E. coli, although it has been implicated in a number of processes in this organism including DNA replication, site-specific recombination, and gene expression. This review presents recent work which suggests that IHF alters the activity of an unusually large number of operons in E. coli. We discuss the possible physiological relevance of the involvement of IHF in gene expression and the hypothesis that IHF is a member of a class of functionally redundant proteins that participate in chromosome structure and multiple processes involving DNA.